Corrugating machines serving as cardboard sheet-manufacturing apparatuses include a single facer that forms a single-faced cardboard sheet, and a double facer that bonds front liner paper to the single-faced cardboard sheet to form a double-faced cardboard sheet. The single facer processes a core paper (corrugating medium) into a waveform, bonds the back liner to form the single-faced cardboard sheet, and the double facer bonds the front liner to this single-faced cardboard sheet to form the double-faced cardboard sheet. A continuous double-faced cardboard sheet manufactured by this double facer is cut to a predetermined width by a slitter scorer, and is cut to a predetermined length by a cutoff device to form a cardboard sheet.
In these corrugating machines, a cutting mark for cutting to the predetermined length is printed on a front surface of the cardboard sheet, a detector detects this cutting mark, and the cutoff device operates on the basis of this detection results to cut the cardboard sheet to the predetermined length. As such corrugating machines, there is, for example, a corrugating machine described in the following PTL 1. In addition, in the manufacture of a cardboard sheet by the corrugating machine, in a case where this cutting mark is not printed, a preprint sheet to which a liner on which the cutting mark is printed is bonded may be used, or the cutting mark may be present on a back surface.